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• rtmp audio out of sync, http works fine

  21 janvier 2014, par marca

  We have encoded and distributed videos for some years now, using FFMPEG to produce h.264/mp4 files that have been working great for us. We have been using HTML mode and fall-backed to flash for browsers that does not support it natively using flowplayer.

  We use cloudfront to serve our files from a s3 bucket and have been using http progressive streaming.

  Recently we started distribute the files in flashmode over rtmp instead, using a cloudfront streaming distribution pointing to the same amazon s3 bucket.

  All good for some weeks, until yesterday when we notice a couple of files with audio sync issues in rtmp mode.
  The same file have no sync problems in flash with direct url to file.

  What can be the case ?

  Not working when streamed via RTMP, but file work with http streaming/progressive.
  You see the sync issue 15 sec's into the video.
  rtmp ://s2xe2avk54qztf.cloudfront.net:1935/cfx/st/mp4:95fvOY255bdPspO3z6tEvGi3Em7/default.mp4
  http://media.shootitlive.com/95fvOY255bdPspO3z6tEvGi3Em7/default.mp4

  Another file that have no sync issue at all.
  rtmp ://s2xe2avk54qztf.cloudfront.net:1935/cfx/st/mp4:P4EuH2TZxfV6BvpupP6dxrrs7gD/default.mp4
  http://media.shootitlive.com/P4EuH2TZxfV6BvpupP6dxrrs7gD/default.mp4

  Both files have the same format for video and audio and have been encoded the exact same way with ffmpeg. It's not player related as we see the audio sync issue on several players and when playing stream in VLC.

• ffmpeg not working with filenames that have whitespace

  1er avril 2017, par cmw

  I’m using FFMPEG to measure the duration of videos stored in an Amazon S3 Bucket.

  I’ve read the FFMPEG docs, and they explicitly state that all whitespace and special characters need to be escaped, in order for FFMPEG to handle them properly :

  See docs 2.1 and 2.1.1 : https://ffmpeg.org/ffmpeg-utils.html

  However, when dealing with files whose filenames contain whitespace, ffmpeg fails to render a result.

  I’ve tried the following, with no success

  ffmpeg -i "http://s3.mybucketname.com/videos/my\ video\ file.mov" 2>&1 | grep Duration | awk '{print $2}' | tr -d
  
  ffmpeg -i "http://s3.mybucketname.com/videos/my video file.mov" 2>&1 | grep Duration | awk '{print $2}' | tr -d
  
  ffmpeg -i "http://s3.mybucketname.com/videos/my'\' video'\' file.mov" 2>&1 | grep Duration | awk '{print $2}' | tr -d
  
  ffmpeg -i "http://s3.mybucketname.com/videos/my\ video\ file.mov" 2>&1 | grep Duration | awk '{print $2}' | tr -d

  However, if I strip out the whitespace in the filename – all is well, and the duration of the video is returned.

  Any help is appreciated !

• Converting mp4 to ogg file format results in a large file

  26 avril 2014, par parags

  I have a MP4 file of 83MB (converted from MOV of about 772MB using FFMPEG).
  For the file to be playable from all browsers from HTML5 video tag, I am converting the MP4 to OGG, again using FFMPEG command

  ffmpeg -i object-creation.mp4 -acodec libvorbis -vcodec libtheora -q:v 5 -q:a 5 object-creation-3.ogg

  The result of the above command is a very large OGG file of around 500 MB. I would certainly not want to upload such huge files to Amazon S3 (which I am using for storage, and distribution).

  Is there something I am missing here ? Is the file not compressed enough ?

  Is it possible to have the resultant file of somewhat manageable size like 80-100 MB without any appreciable loss in quality over what is seen in MP4 format ? Why is it that even the source file is 83MB, the resultant file is too big in comparison ?

  Thanks
  Parag